Novak Djokovic said his encounters with Roger Federer were always decided by "a couple of points here and there", but the 23-year-old Serb was being modest in his post-match verdict after beating the world No 2 in the final of the Dubai Duty Free Championships on Saturday night. Djokovic's 6-3, 6-3 victory, achieved in just 71 minutes, was more emphatic than the scoreline suggested and underlined his current hold on Federer.

Djokovic, whose current 15-match winning streak goes back to last November, beat Federer in straight sets on his way to victory in the Australian Open and the Swiss brought the best out of the Serb for the second time in a month. The world No 3 served with confidence, dropping only four points on serve in the first set, and had Federer under constant pressure with the quality of his returns.

After Federer enjoyed his only good spell of the match Djokovic's response was formidable. Federer led 3-1 in the second set but won only five more points as Djokovic secured his third successive title here. He broke Federer four times in total and forced him into a stream of errors with the quality of his ground strokes. Federer, who agreed that he had not played well, kept mis-hitting as he was hurried into his shots.

"He made a lot of unforced errors," Djokovic said. "It was obvious he was not feeling good on the court. You have those days. It's normal. Even for somebody like him who's always playing so well in the later stages of the tournament, it happens. On the other side I played great and always made him play an extra shot.

"I had to put him out of his comfort zone. That's what I did. I returned well and I served really well. From the baseline I was working the ball well, changing the pace of the ball. I guess that was the reason he made a lot of mistakes."

Twelve months ago Djokovic was struggling with his serve, but his confidence has risen since he ironed out some technical flaws. "I'm a different player to last year – I have a serve," he laughed.

"Last year the serve was not there and I was struggling a lot. I was using a lot of energy. Now I get to win some free points with my serve, which is important. I didn't want to change my serve. It just happened like that.

"I had some trouble with the shoulder and I just got into a bad habit with my service action. It was different to what had been working quite well for me in 2008 and 2009. Now all that is behind me. I have my serve back."

He added: "This match has probably been one of the best that I played this year. I want to keep it up, definitely. I feel physically well, fit, mentally motivated to do even more coming up to Indian Wells and Miami, where I haven't done well in recent years."

Djokovic said he had talked too much in the past about his ambitions and now wanted to take one tournament at a time. "I just want to be playing consistently well," he said. "I want to keep up the good form that I have, stay fit and just take care of my health and my physical condition. I have done it really well in the last two months."

Juan Martin del Potro, who is returning after a year out with a wrist injury, maintained his recent progress when he beat Mardy Fish 6-1, 7-5 in the semi-finals of the Delray Beach International.

The 2009 US Open champion was due to meet Serbia's Janko Tipsarevic in last night's final.

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